5.12.12 for macOS

Following database backend is distributed with this version:

1. SQLite (distributed with Qt): Built in the package using command -sql-sqlite.

All builds have -no-openssl -securetransport, which means that Secure Transport library provided by macOS is used for TLS Backend.
This backend is supported by Qt since Qt 5.6.

All builds have -no-icu because I think the ICU library is too big and, in most of the conditions, useless for common users.